Venezuelan Equine Encephalitis (VEE) has been implicated as a human teratogen. We are studying the pathogenesis of this infection in pregnant rhesus monkeys. The vaccine strain TC-83 VEE produces porencephaly, hydrocephaly and micrencephaly when inoculated intracerebrally into 100 day fetuses. Cataracts have developed in fetuses that were delivered after 140 days gestation. We have developed a rhesus monkey cytomegalovirus (Rh CMV) model. This virus produces CNS abnormalities in the fetus when inoculated intraamniotically into CMV antibody positive pregnant rhesus monkeys.